' CandidatusPhytoplasma phoenicium' associated with almond witches'-broom disease: from draft genome to genetic diversity among strain populations
Background: Almond witches-broom (AlmWB), a devastating disease of almond, peach and nectarine in Lebanon, is associated with Candidatus Phytoplasma phoenicium. In the present study, we generated a draft genome sequence of Ca. P. phoenicium strain SA213, representative of phytoplasma strain populations from different host plants, and determined the genetic diversity among phytoplasma strain populations by phylogenetic analyses of 16S rRNA, groEL, tufB and inmp gene sequences. Results: Sequence-based typing and phylogenetic analysis of the gene inmp, coding an integral membrane protein, distinguished AlmWB-associated phytoplasma strains originating from diverse host plants, whereas their 16S rRNA, tufB and groEL genes shared 100 % sequence identity. Moreover, dN/dS analysis indicated positive selection acting on inmp gene. Additionally, the analysis of Ca. P. phoenicium draft genome revealed the presence of integral membrane proteins and effector-like proteins and potential candidates for interaction with hosts. One of the integral membrane proteins was predicted as BI-1, an inhibitor of apoptosis-promoting Bax factor. Bioinformatics analyses revealed the presence of putative BI-1 in draft and complete genomes of other Ca. Phytoplasma species. Conclusion: The genetic diversity within Ca. P. phoenicium strain populations in Lebanon suggested that AlmWB disease could be associated with phytoplasma strains derived from the adaptation of an original strain to diverse hosts. Moreover, the identification of a putative inhibitor of apoptosis-promoting Bax factor (BI-1) in Ca. P. phoenicium draft genome and within genomes of other Ca. Phytoplasma species suggested its potential role as a phytoplasma fitness-increasing factor by modification of the host-defense response.
Vorschau
Zitieren
Zugriffsstatistik
Rechte
Nutzung und Vervielfältigung:
Alle Rechte vorbehalten